Battery Challenge - Voltage of Two Metals in Different Solutions

Rebecca and Amelie


Abstract:


In our experiments, we recorded the voltage of two metal sheets (copper and aluminum) that were emersed in five different solutions. The solutions were made of 300 ml of one substance (Coke Zero, carrot juice, apple juice, Kool-Aid and melted chocolate) mixed with 100 ml of salt water. We discovered that the Kool-Aid actually created the most voltageof the five solutions and that the carrot juice was the least productive. The Kool-Aid also had the highest current of the three we recorded (apple juice, Kool-Aid and melted chocolate.)

Introduction:


The purpose of these experiments was to discover the conductibility of each of the five solutions mentioned above through recording and comparing the highest amounts of voltage produced by the metals in the different solutions. Our independent variable were the five solutions of either 300 ml of Kool-Aid, Coke Zero, carrot juice, apple juice or melted chocolate with an added 100 ml of salt water. The 100 ml of salt water was the similarity in our 5 solutions. We hypothesized that the carrot juice would create at least two times more voltage than our worst tested solution because of our results from the experiment of the class before. In that lab, we tested the voltage and current of copper and aluminum sheets emersed in salt water through an ammeter. Since our results were somewhat good in that test and noticing the fact that our teacher had given this substance to experiment before all others, we thought carrot juice, which consists of water, would be the most productive of the solutions. Therefore, we based the rest of our expectations using the same thought. This made the melted chocolate as the least likely to create high amounts of voltage. Our expectations and place order (from most likely to least likely to create high amounts of voltage) were as followed:
1. Carrot Juice (Boiled Carrots in Water)
2. Apple Juice
3. Kool-Aid
4. Coke Zero
5. Melted Chocolate



("PROCEDURE" OR PLAN AND "DATA": REBECCA)

Graphs are shown in document below.



Experiment 1: 300 ml of Coke Zero with 100 ml salt (NaCl3) water:

Voltage: starting at 0.57 volts but descending
  • 0.525 volts
  • 0.469 volts
  • 0.36... volts
Observations and Additional Notes: As the metals got closer to one another, the voltage decreased. Therefore, we established a set distance (metals touching the glass beaker at opposite sides) for each experiment so that we can record more accurate and precise measurements. I also noticed that as the carbon dioxide escaped from the solution, the voltage of the "battery" decreased. Also, the meatls would float in the solution, most likely caused by the carbon dioxide.

Conclusion: Our first measurements (o.57 to 0.525 volts) were about a third of the voltage achieved in a normal battery (1.5 volts.) This means that only three pairs of the metals immersed in three of these solutions would give off equal or possibly more voltage than an average battery. However, this homemade battery which includes Coke Zero and salt water would not last very long since our data shows the voltage decreasing at an alarming pace. Therefore, this solution would not create a "better battery."

Experiment 2: 300 ml of carrot juice (boiled carrots in water) with 100 ml of salt (NaCl3) water:

Voltage: starting at 0.47 volts but descending
  • 0.324 volts
  • 0.281 volts
  • 0.270... volts
Observations and Additional Notes: When we pull the meatls closer to one another, the voltage increased than decreased. When we quickly seperate them, the voltage increased to 0.300 volts. (Our measurements above were recorded when the metals were touching the opposite sides of the beaker, in the same position as the first experiment. Only after our data was noted that we started randomly experimenting with the metals, noting down the changes in voltage.)

Conclusion: The experiment proves our hypothesis to be incorrect. The carrot juice mixed in with the salt water was in fact, less productive than we had planned. Though we have not already experimented with our last three solutions (melted chocolate, kool-aid and apple juice) we can already conclude that the carrot juice will not create the most voltage since it has already been surpassed by Coke Zero. However, an element that could have altered experiment 2 is the temperature of the solution. When we tested the metals in the solution of carrot juice and salt water, it was still slightly warm. Therefore, our data may not be completely exact even though we can conclude that carrot juice would definitly not make a better battery.

Experiment 3: 300 ml of Kool-Aid with 100 ml of salt (NaCl3) water:

Voltage: starting at 0.582 volts but descending
  • 0.564 volts
  • 0.554 volts
  • 0.545...volts
Current: starting at 12.01 ma but descending
  • 6.2 ma
  • 4.5 ma
  • 4.2 ma
Observations and Additional Notes: Our Kool-Aid consists of a whole package of the Kool-Aid powder though I am not certain about definite measurements. I believe that all the powder was dissolved into the 300 ml of water. For this experiment, we decided to measure the current passing through the solution and will continue recording the current for the last two experiments.

Conclusion: The Kool-Aid has about the same voltage of Coke Zero but much more than carrot juice. The carrot juice seems to be doing much worse than we expected. The current for the Kool-Aid was fairly high, starting at about 12 ma.

Experiment 4: 300 ml of apple juice with 100 ml of salt (NaCl3) water:

Voltage: starting at 0.465 volts
  • 0.406 volts
  • 0.382 volts
  • 0.359 volts
Current: starting at 0.987 ma but descending rapidly
  • 0.86 ma
  • 0.645 ma
  • 0.003...ma
Observations and Additional Notes: The apple juice and salt water solution is still somewhat cold. Could the temperature of the substance affect the experiment?

Conclusion: The apple juice is evidently, a poor conductor. The highest amount of voltage the apple juice produced is only 0.045 volts greater than the highest amount of voltage created by the metals in the carrot juice, which so far, is the least effective solution.

Experiment 5: 150 ml of melted chocolate with 50 ml of salt (NaCl3) water:

Voltage: starting at 0.288 volts
  • 0.282 volts
  • 0.278 volts
  • 0.276 volts
Current: starting at 0.811 ma
  • 0.786 ma
  • 0.755 ma
  • 0.727 ma
Observations and Additional Notes: Since we didn't have enough chocolate to have a melted solution of 300 ml, we had experiment with half our planned measurements. We tested with 150 ml of melted dark chocolate and 50 ml of salt water, a total of 200 ml. Therefore, we could estimate the results of our would-be 400 ml substance. If you multiply, our shown results by two, then you would get an idea of how conductive chocolate is.

Conclusion: The voltage for 300 ml of melted chocolate would then be:
  • 0.576 volts
  • 0.564 volts
  • 0.556 volts
  • 0.552 volts
I do not know if we would have to multiply the current by two or not. Does the current depend on certain measurements of the solution containing the two metals?

Evaluation

- Amelie